Method for fabricating a dual work function semiconductor device and the device made thereof

摘要

A method for manufacturing a dual work function semiconductor device and the device made thereof are disclosed. In one aspect, a method includes providing a gate dielectric layer over a semiconductor substrate. The method further includes forming a metal layer over the gate dielectric layer. The method further includes forming a layer of gate filling material over the metal layer. The method further includes patterning the gate dielectric layer, the metal layer and the gate filling layer to form a first and a second gate stack. The method further includes removing the gate filling material only from the second gate stack thereby exposing the underlying metal layer. The method further includes converting the exposed metal layer into an metal oxide layer. The method further includes reforming the second gate stack with another gate filling material.

主权项

1. A method of manufacturing a dual work function semiconductor device, the method comprising:
providing a semiconductor substrate; providing a gate dielectric layer on and in contact with the semiconductor substrate; forming a metal layer having a thickness on and in contact with the gate dielectric layer, forming a first gate filling material on and in contact with the metal layer; patterning the gate dielectric layer, the metal layer and the first gate filling material to form a first gate stack and a second gate stack; after patterning, introducing dopants into substrate regions adjacent the first and second gate stacks and annealing to activate the dopants, thereby forming activated source/drain regions for both first and second gate stacks; after annealing, selectively removing the first gate filling material only from the second gate stack thereby exposing the underlying metal layer; after selectively removing, replacing the first gate filling material removed from the second gate stack with a second gate filling material formed of an oxygen-rich metal to form a replacement gate stack comprising the second gate filling material formed on the underlying metal layer; and thermally treating to supply oxygen atoms from the second gate filling material to the underlying metal layer to convert the underlying metal layer of the replacement gate stack into a metal oxide layer.